Closed circuit heat transfer devices



June 20, 1967 c. COWAN CLOSED CIRCUIT HEAT TRANSFER DEVICES Filed Feb.23, 1966 m'myrrve 194212-67 (av/rm I arr-02mg:

Patented June 20, 1967 3,326,278 CLOSED CIRCUIT HEAT TRANSFER DEVICESRobert C. Cowan, 578 I-Iarbison St, Winnipeg, Manitoba, Canada FiledFeb. 23, 1966, Ser. No. 529,415 2 Claims. (Cl. 165.105)

ABSTRAQT OF THE DISCLGSURE A closed circuit heating system having aboiler with radiating tubes extending upwardly therefrom through whichvaporized fluid passes from the boiler to a sloping header tank and acondensate return conduit extending from the lower end of said slopingheader tank to said boiler below the normal fluid level therein, saidreturn conduit being shielded to prevent cosling thereof by air passingsaid radiator tubes.

My invention relates to new and useful improvements in heating devices,more specifically heating devices of the closed circuit type whereinfluid is heated in the boiler and vaporized, the vapour then passingthrough heat radiating tubes to a header tank, and the condensate thenreturning to the boiler.

The principal object and essence of my invention is to provide a deviceof the character herewithin described which improves the circulation ofthe vapour and condensate thereby increasing the efiiciency of thedevice.

Another object of the invention is to provide a device of the characterherewithin described in wh'ch the condensate conveyor tubes are shroudedfrom the action of the air passing through the radiator formed by thevapour conveying tubes thus maintaining the returning condensate at atemperature higher than normal.

A yet further object of the invention is to provide a device of thecharacter herewithin described in which the condensate in the headertank flows to one end of the header tank.

Another object of the invention is to provide a device of the characterherewithin described which is simple in construction, economical inmanufacture, and otherwise well suited to the purpose for which it isdesigned.

With the foregoing in view, and all those objects, purposes o-radvantages which may become apparent from consideration of thisdisclosure and specification, the present invention consists of theinventive concept embodied in the method, process, construction,arrangement of parts, or new use of the same, as herein particularlyexemplified in one or more specific embodiments of such concept,reference being had to the accompanying figures in which:

FIGURE 1 is a side elevation, sectioned in part showing my device insitu with a conventional hot air system.

FIGURE 2 is a front elevation of my device per se.

FIGURE 3 is an end view of FIGURE 2.

FIGURE 4 is a sectional view along the line 4-4 of FIGURE 2.

In the drawings like characters of reference indicate correspondingparts in the different figures.

Proceeding therefore to describe my invention in detail, referenceshould first be made to FIGURE 1 in which illustrates a furnace casinggenerally having my device collectively designated 11 situatedtherewithin for the production of heat.

A fan 12 draws cold air through duct 13, through filters 14, and thenceto duct 15 communicating with the furnace casing 10.

After passing through the heat radiating portion of my device 11, itpasses to the hot air distribution duct 16 in the usual manner.

My device collectively designated 11, includes a boiler 17 having asubstantially rectangular base 18 and a hemispherical upper wall 19.

Electric heating elements or similar heating means 20 extend into thelower portion of the boiler and may be connnected to a source ofelectrical energy (not illustrated) via terminals 21.

The boiler 17 is partially filled with fluid, preferably water,reference character 22 illustrating the water. level which is at alltimes above the heating element 20.

This provides a vapour space 23 above the water level, said vapour beingsteam formed by the heating of the water by means of a heating element,or elements 20.

A radiator collectively designated 24 surmounts the boiler 17 andcomprises a pair of side plates 25 between which is situated a pluralityof vapour conveying and heat radiating tubes 26. The lower ends 27 ofthese tubes communicating with the area 23 of the boiler and these tubesare preferably finned as shown at 28 to increase the heat radiatingeffect thereof, it being understood that the air passing through thefurnace casing 1d, also passes by the finned tubes 26.

A header tank 2% surmounts the upper ends of these tubes and this headertank is substantially rectangular when viewed in plan. It comprises apair of spaced and parallel longitudinal side walls 30 and a pair ofspaced and parallel transverse end walls 31.

A base wall 32 and an upper wall 33 complete the header tank and theupper ends 34 of the tubes 26 extend through the base wall 32 andproject above the level thereof as clearly shown in FIGURE 2. This is toprevent condensate forming within the header tank, from flowingdownwardly through the tubes 26.

It will be noted that both the base wall 32 and the upper wall 33 of theheader tank 29 slope downwardly from one end wall 31 towards the otherend Wall so that condensate forming within the header tank, flows to theright-hand end Wall 31 (with reference to FIG- URE 2).

Adjacent the right hand end wall 31, I have provided a pair ofcondensate conveying ducts 35, the upper ends 36 of which are flush withthe base wall 32 of the header tank and communicate therewith.

These ducts extend downwardly to the boiler and communicate with theinterior thereof, the lower ends 37 of these ducts terminating adjacentthe base 38 and below the fluid line 22.

In order to maintain the temperature of the condensate flowing down thetubes 35, at the h ghest possible temperature, I have provided a pair ofbaflles 39 situated at right angles to one another and extending fromthe base 32 of the header tank to the upper side 40' of the boiler.

These shroud the condensate conveying ducts 35 from the effect of theair passing through the radiator, it being understood that said air ismoving in the direction of arrow 41.

The advantage of sloping the base 32 of the header from one side end tothe other is to permit the condensate conveying duct to be situated atone end of the radiator and away from the tubes 26.

This prevents cool spots from occurring within the radiator, which coolspots have occurred previously when the return ducts have been centrallylocated.

Also by shrouding the condensate conveying ducts 35, the condensaterunning down these ducts will not cool down so fast and will be of ahigher temperature than normal so that less time and heat energy isrequired to return the condensate up to the desired operatingtemperature.

This will result in a faster build up of heat in the boiler in a shortertime cycle thus improving the efliciency of the furnace.

I prefer to use a pair of condensate conveying ducts 35 so that thecondensate is withdrawn more rapidly and danger of flooding thecondensate return duct is eliminated.

Since various modifications can be made to the invention hereindescribed Within the scope of the inventive concept disclosed, it is notintended that protection of the said invention should be interpreted asrestricted to the modification or modifications or known parts of suchconcept as have been particularly described, defined, or exemplified,since this disclosure is intended to explain the construction andoperation of such concept, and not for the purpose of limitingprotection to any specific embodiment or details thereof.

What I claim as my invention is:

1. In a heat exchange device, the combination of a boiler adapted to bepartly filled with fluid whereby to provide space for fluid vapour inthe upper portion of the boiler, a set of vapour conveying and heatradiating tubes communicating with and extending upwardly from the topof said boiler, a header tank provided at the upper end of said tubes,said header tank being substantially rectangular when viewed in plan andincluding a pair of spaced and parallel longitudinal side walls and apair of spaced and parallel transverse end walls, an upper wall and abase wall sloping downwardly from one transverse end wall towards theother transverse end wall, to facilitate the drainage of fluidconcentrate towards said other transverse end wall, the upper ends ofsaid tubes extending in said tank above the base wall thereof, and atleast one condensate conveying duct extending from said header tankadjacent said one transverse end Wall to a point in the lower portion ofsaid boiler below the normal level of fluid therein, whereby vapourcondensate in the tank may gravitate through said duct into said boiler,and baflle means shrouding said condensate conveyor duct to reduce thecooling of said condensate conveyor duct.

2. The device according to claim 1 in which said baflle means shroudingsaid condensate conveying tube from the air passing by said vapourconveying and heat radiating tubes, comprises a pair of verticallysituated plates extending at right angles from one another and extendingin spaced relationship the length of said condensate conveyor tubebetween the upper end of said boiler and the base wall of said headertank.

References Cited UNITED STATES PATENTS 1,662,440 3/1928 Rushmore 1651,898,571 2/1933 Prince -105 X 2,712,054 6/1955 King 2l9365 2,734,9892/1956 Hoffman 219-365 X ROBERT A. OLEARY, Primary Examiner.

A. W DAVIS, Assistant Examiner.

1. IN A HEAT EXCHANGE DEVICE, THE COMBINATION OF A BOILER ADAPTED TO BEPARTLY FILLED WITH FLUID WHEREBY TO PROVIDE SPACE FOR FLUID VAPOUR INTHE UPPER PORTION OF THE BOILER, A SET OF VAPOUR CONVEYING AND HEATRADIATING TUBES COMMUNICATING WITH AND EXTENDING UPWARDLY FROM THE TOPOF SAID BOILER, A HEADER TANK PROVIDED AT THE UPPER END OF SAID TUBES,SAID HEADER TANK BEING SUBSTANTIALLY RECTANGULAR WHEN VIEWED IN PLAN ANDINCLUDING A PAIR OF SPACED AND PARALLEL TRANSVERSE END WALLS, AN A PAIROF SPACED AND PARALLEL TRANSVERSE END WALLS, AN UPPER WALL AND A BASEWALL SLOPING DOWNWARDLY FROM ONE TRANSVERSE END WALL TOWARDS THE OTHERTRANSVERSE END WALL, TO FACILITATE THE DRAINAGE OF FLUID CONCENTRATETOWARDS SAID OTHER TRANSVERSE END WALL, THE UPPER ENDS OF SAID TUBESEXTENDING IN SAID TANK ABOVE THE BASE WALL THEREOF, AND AT LEAST ONECONDENSATE CONVEYING DUCT EXTENDING FROM SAID HEADER TANK ADJACENT SAIDONE TRANSVERSE END WALL TO A POINT IN THE LOWER PORTION OF SAID BOILERBELOW THE NORMAL LEVEL OF FLUID THEREIN, WHEREBY VAPOR CONDENSATE IN THETANK MAY GRAVITATE THROUGH SAID DUCT INTO SAID BOILER, AND BAFFLE MEANSSHROUDING SAID CONDENSATE CONVEYOR DUCT TO REDUCE THE COOLING OF SAIDCONDENSATE CONVEYOR DUCT.